Question

How does a cold or hot sodium hydroxide solution impact reactions, particularly with DDQ? Would there be same results in either temperature?

Answer 1

DDQ does not react directly with NaOH. Rather, it is the chlorine which may be released from it.

When chlorine reacts with cold solution of sodium hydroxide, the disproportionation goes to lower oxidation states:

Cl₂ + 2KOH ⟶ KCl + KClO + H₂O

with hot solution the oxidation state of chlorine goes up to +V:

3Cl₂ + 6KOH ⟶ KClO3 + 5KCl + 3H₂O

Higher temperature promotes the formation of hypochlorous acid through hydrolysis of hypochlorite and so, quickens up the reaction.